The technical field relates generally to the field of navigation systems, and more particularly to a navigation device for receiving satellite broadcast distribution of map data and related methods.
Navigation systems that display map images corresponding with a geographic location are widely available. In a typical navigation system, a processor is connected with a memory system having data corresponding to a geographic map image, such as a geographic information systems (GIS) database. Oftentimes, the geographic map images are stored as rastor graphic data, bit map data, or vector graphic data. In many navigation systems, the memory system is a compact disk-read only memory (CD-ROM), and the map images are stored on compact disks (CDs).
Navigation systems are installed in automobiles as a factory option or as an aftermarket addition, and have become a popular feature with rental car companies. In many examples, the navigation system is connected with a position sensing device, such as a global positioning system (GPS) receiver, and the correct geographic map for the vehicles location is automatically displayed in correspondence with the GPS determined location of the vehicle.
One drawback of current navigation systems is the difficulty in which map images are distributed to users of the systems. In the case of CD-ROM based map images, new CDs must be mailed to the users of the system, and the users have to manually manage their inventory of CD-based map images. Another drawback of current navigation systems, is that when the user drives out of a range of the map images on the CD currently loaded in the CD-ROM drive, the user must manually find and insert a CD for the new location.
It was recognized by the present inventor that it would be advantageous to remove the expense, hassle, and difficulties associated with updating and maintaining a CD-based map inventory for navigation devices. In response to this recognition, the present inventor conceived of a method and an apparatus for distributing map data using satellite broadcast transmission. A satellite orbiting the earth broadcasts map data, which is updated and transmitted to the satellite from a ground station in communication with the satellite. The navigation device is especially adapted to receive broadcast communication from the satellite. After receiving a broadcast map, the navigation device determines if the map corresponds with the location of the vehicle. To determine location, the navigation device includes a location detection device such as a GPS receiver. If the map corresponds with the location of the navigation device, then the map is loaded in memory and displayed on a screen connected with the navigation device.
A navigation device according to an aspect of the present invention includes a central processing unit, or other processor, in communication with a computer storage medium, such as the various types of random access memory, read-only memory, optical disk storage technology such as compact disk-read only memory, hard disk drive devices, compact disk recordable, memory stick, and the like. The navigation device further includes a satellite broadcast receiver in communication with the central processing unit and with the computer storage medium. The satellite broadcast receiver receives broadcast map data from a satellite. The map data is stored in the computer storage medium, after which map images corresponding with the map data are presented on a display connected with the navigation device. The navigation device may further include a global positioning system receiver in communication with the central processing unit. The global positioning system receiver is used for determining a geographic location of the navigation device.
A method of providing map data to a navigation device according to an aspect of the present invention includes a first operation of receiving a broadcast transmission of map data corresponding with a first geographic location. In a second operation, determining a second geographic location corresponding with the geographic location of the navigation device. In a third operation, comparing the first geographic location to the second geographic location. The geographic location data may include latitude and longitude data. The comparing operation includes determining if the map data includes a map image for the geographic location of the navigation device. In a fifth operation, in response to the comparing operation, storing the map data in a computer storage medium. The operation of determining a second geographic location includes receiving a global positioning satellite signal, which is used by the global positioning system receiver to determine the location of the navigation device.
The method may further include the operation of displaying a map image corresponding with the map data. The map data can be in a bit-map format, a vector graphic format, a rastor graphic format, in a geographic information system format, or the like. The method may further include the operation of determining a direction of travel of the navigation device, and in a second comparing operations, comparing the first geographic location with the direction of travel of the navigation device and in response to the second comparing operation, storing the map data in the computer storage medium.